Refer to the accompanying data display that results from a sample of airport data speeds in Mbps. Complete parts (a) through (c) below. TInterval (13.046,22.15) x overbarequals17.598 Sxequals16.01712719 nequals50 a. Express the confidence interval in the format that uses the "less than" symbol. Given that the original listed data use one decimal place, round the confidence interval limits accordingly. 13.05 Mbpsless thanmuless than 22.15 Mbps (Round to two decimal places as needed.) b. Identify the best point estimate of mu and the margin of error.
Accepted Solution
A:
Answer:Point estimation of the mean = 17.6Error = 4.695% CI: 13.0 ≤ μ ≤ 22.2The distribution can be approximated to a normal because the sample size n=50 is bigger than 30.Step-by-step explanation:We have this information:- Sample mean:[tex]\bar{X}=17.598[/tex]- Sample standard deviation[tex]s=16.01712719[/tex]- Sample size[tex]n=50[/tex]For now on, we round to one decimal place.The best estimation for the population mean is the sample mean[tex]\mu=\bar{X}=17.6[/tex]The margin of error is equal to the t-value multiplied by the sample standard deviation and divided by the sample size.The t value depends on the degrees of freedom and the width of the confidence interval. In this case it is a 95% CI and the degrees of freedom are 49. For this conditions, the t-value is t=2.01.Then, the margin of error is[tex]E=t_{49}*\sigma/\sqrt{n}=2.01*16.0/\sqrt{50}=4.553[/tex]Then, the confidence interval can be constructed as:[tex]\bar{X}-t\sigma/\sqrt{n}\leq\mu\leq\bar{X}-t\sigma/\sqrt{n}\\\\17.6-4.6\leq \mu \leq 17.6+4.6\\\\ 13.0\leq \mu \leq 22.2[/tex]